As a color filter formed above a device in order to color a solid-state image sensor or a liquid crystal display, a color filter formed from a yellow filter layer, a magenta filter layer, and a cyan filter layer that are formed adjacent to each other on the same plane above a substrate, or a color filter formed from a red filter layer, a green filter layer, and a blue filter layer are known. In these filter layers, a band-shaped pattern or a mosaic pattern is formed.
As a method for producing the above-mentioned color filter, various methods have been proposed. Among them, a so-called color resist method, in which a step of carrying out patterning by exposing and developing a dye-containing photosensitive resin composition is repeated a required number of times, has been widely put into practice.
The color resist method is a method for producing a color filter by a photolithographic method using a colored radiation-sensitive composition in which a pigment is dispersed in various photosensitive compositions; this method is considered to be a method suitable for production of a color filter for a large screen, high resolution color display since it is stable to light, heat, etc. due to a pigment being used and the positional precision is sufficient due to patterning being carried out by a photolithographic method.
When a color filter is produced as described above by a pigment dispersion method in which a pigment is dispersed, a color filter is obtained by forming a coating by coating a glass substrate with a radiation-sensitive composition using a spin coater, a roll coater, etc., carrying out pattern exposure and developing of this coating so as to obtain colored pixels, and carrying out this procedure for the number of hues required. As the pigment dispersion method, a negative-working photosensitive composition in which a photopolymerizable monomer and a photopolymerization initiator are used for an alkali-soluble resin has been disclosed (ref. e.g. Patent Documents 4 and 5).
On the other hand, in recent years, higher resolution has been desired for a color filter for a solid-state image sensor. However, in the above-mentioned conventional pigment dispersion system, the resolution does not improve, there is the problem that color unevenness occurs due to coarse pigment particles, etc., and it is therefore not suitable for application where a fine pattern is required as for a solid-state image sensor. In order to solve such a problem, the use of a dye has been proposed in the art (ref. e.g. Patent Documents 1 and 2). Furthermore, a positive-working photosensitive composition has also been disclosed (ref. e.g. Patent Documents 3 and 4).
Moreover, Patent Document 6 discloses a colorant-containing curable composition formed from a colorant, the colorant comprising a compound represented by Formula (1) below and/or a tautomer thereof.
(In Formula (1), R1 to R4 independently denote a hydrogen atom, a halogen atom, —S—R5, or —S—R6. S denotes a sulfur atom, and R5 denotes an alkyl group containing an oxygen atom in the form of an ether bond and may further have a hydroxy group as a substituent. R6 denotes an alkyl group having a hydroxy group. At least one of R1 to R4 denotes —S—R5.)
Patent Document 7 discloses a curable coloring composition comprising a polymer dye, the polymer dye being at least one type selected from the group consisting of a copolymer of at least one type of dye monomer represented by Formula (P) below and at least one type of colorless monomer having at least one ethylenic double bond and a polymer derived from at least one type of dye monomer represented by Formula (P) below.
(In Formula (P), Ra1 and Ra2 mutually independently denote a hydrogen atom, an aliphatic group, an aryl group, or a heterocyclic group, L1 denotes any one of (L-1), (L-2), (L-3), and (L-4) below, and i denotes 0 or 1. Q denotes a dye residue that is formed by removing a hydrogen atom from any possible position of a dye represented by Formula (1) below.)
(In (L-1) to (L-4), Ra3 and Ra4 mutually independently denote a hydrogen atom, an aliphatic group, an aryl group, or a heterocyclic group. In (L-1) to (L-4), the group having a dye residue and an ethylenic double bond may be bonded to either side.)
(In Formula (1), R301 to R306 mutually independently denote a hydrogen atom or a substituent. When at least two of R301 to R306 are at adjacent positions, they may be bonded to each other to form a 5- to 6-membered ring, and the ring may further have a substituent.)